Researchers have found a way to produce high-quality methane gas – a main component of the natural gas used for energy – from the coffee grounds left behind after instant coffee production.

The breakthrough was made as part of a pilot project by researchers at the Paul Scherrer Institute (PSI), a member of the Swiss Federal Institutes of Technology Domain, in cooperation with Swiss food giant Nestlé.

Leftover moist coffee grounds from Nestlé’s instant coffee production were subjected to extremely high pressure and temperature conditions (about 450 degrees Celsius) at an experimental PSI pilot facility. This treatment allowed mineral salts contained in the grounds to be extracted and reused, while the remaining compounds were converted to methane gas using a catalyst.